1. Field of the Invention
This invention relates to a powder compacting press and particularly to such a press having multi-motion movement and wherein the pressed parts are ejected upwardly providing more consistency in the composition of the pressed metal parts at higher pressing speeds and previously attainable in mechanical powder presses. The press is useful for compacting metal, ceramic, and other particulates into useful articles, such as bushings.
2. Brief Description of the Prior Art
Heretofore powder presses have generally been classified as hydraulic and mechanical presses. The mechanical presses have been further defined by the number of punches for ejecting the finished part and by the direction of the ejection either upwardly or downwardly. Examples of single punch presses are disclosed in U.S. Pat. Nos. Stokes et. al. 2,389,561; Smith 3,640,654; Claus 1,607,389; DeSantis 4,053,267; DeSantis et al. 3,822,974; Seelig 2,570,989 and Hall 2,867,844. Examples of dual ejection mechanical presses are disclosed in Hurley et al. 3,764,244; Johannigman 3,168,759; Hara et al. 3,635,617; Belden 3,172,156; Smith 3,337,916 and Stokes et al. 2,499,980. Hydraulic power has been used in powder metallurgy presses both for pressing and/or ejection. Various types of hydraulic presses are shown in Carrieri 4,068,520; Hermes 3,587,136; Weidner 2,556,951; Haller 2,640,325; Haller 3,191,232; Whipple 2,253,003; Cutler 2,338,491; Vinson 3,414,940; Graf et al. 3,460,202 and Haller 3,492,696. Rotary presses have also been used, for example see Shapiro 3,677,673.
It is well known in the art of powder pressing that it is important that the density split be substantially in the middle of the pressed part. In the case of a single level part, that is, a part having opposed planar surfaces, such a density split is relatively easy to obtain. In the case of a part having plural levels, however, such a density split is not only difficult to obtain but requires significant modifications to the press. Such modifications comprise a configuration of the punches required, the die table, and the means for ejecting the part. Heretofore mechanical powder metal compacting presses have not been altogether satisfactory from the standpoint of part consistency and production speed. The present invention provides a means for obtaining substantial part consistency even in dual or multi-level parts and provides high production speeds on the order, for example of 1100 parts per hour. The mechanical press of the invention will produce parts on the order of twice as fast as competitive hydraulic presses.